Manuel Pellegrini's apology for his outburst over referee Jonas Eriksson has not spared him a UEFA disciplinary charge.

The European governing body announced the opening of proceedings against the Manchester City manager on Friday evening, hours after he had used a press conference to backtrack on his comments following their 2-0 loss to Barcelona in the Champions League on Tuesday night.

"Following an investigation by the UEFA disciplinary inspector, UEFA has today opened disciplinary proceedings against Manuel Luis Pellegrini concerning the press interviews given to media after the above-mentioned match," a UEFA statement said.

"The Manchester City FC head coach is charged for violation of the general principles of conduct (Art.11 of the 2013 UEFA disciplinary regulations).

"The case will be dealt with by the UEFA control and disciplinary body on Friday 28 February."

In his post-match press conference on Tuesday night, Pellegrini launched an astonishing attack on the official, claiming Eriksson was "not impartial", suggesting he was trying to make amends for previous perceived injustices against Barca and questioning why a Swedish referee was appointed to the fixture.

The 60-year-old was upset after a match at the Etihad Stadium which hinged on a controversial penalty conceded by Martin Demichelis, who was consequently sent off.

On Friday, Pellegrini expressed regret over the outburst and tried to tone down his remarks, albeit too late to change UEFA's mind.

Pellegrini said: "When you lose a game the way we lost against Barcelona, you are frustrated, you are angry.

"Maybe I said some things I didn't mean, so I apologise for what I said.

"Also I want to clarify what I said, I didn't make any serious accusations to anyone, not to the referee, not to UEFA, not to anyone.

"It is not my way to act to criticise the referee, but in that case it was not a good day and he decided the game - but not with the intention to benefit Barcelona or damage Manchester City.

"He was in a bad day with very bad luck."

Pellegrini was most apologetic on the issue of nationality, admitting it was a mistake to suggest a referee from Sweden was not prepared for such high-profile fixtures.

He said: "I am sure this is a good referee because UEFA is always evaluating all the referees and if he is not a good referee, he is not in the UEFA staff.

"The thing I said in that moment doesn't mean what I think.

"I didn't say any serious accusation about Sweden, just that it was not the most important league in Europe and that is not an offence."

Pellegrini did not contest Demichelis' contentious foul on Lionel Messi, but claimed it occurred outside the box and that Jesus Navas was fouled in the build-up.

He has not changed those views but accepts he said too much after the game, having been thinking aloud in the heat of the moment.

Pellegrini said of the official: "I felt from the beginning his criteria was not the same for both teams.

"I think he had a bad day - everyone can have a bad day - but I didn't say that intentionally he didn't give fouls for us or did give fouls for Barcelona.

"I said from the beginning it was not the same criteria. I repeat, a bad day, not dishonest.

"The third thing I said was that it was not a good idea for a referee that damaged Barcelona against Milan to referee the game, because if the same thing happened in the Barcelona box and Barcelona lost the game 1-0 with that penalty and one player sent off, all around Barcelona they would say the same referee did it again.

"It is my idea. I repeat, I didn't have any serious accusation, not against UEFA, not against the referee, not against Sweden, not against anyone.

"It was my way of thinking and I was angry."

The defeat leaves City facing a monumental task to reach the Champions League quarter-finals when they travel to the Nou Camp for the second leg in three weeks' time.

Not surprisingly, talk of the quadruple has also subsided but Pellegrini insists the players will not be badly affected as they host Stoke in the Barclays Premier League this weekend.

Pellegrini said: "They are absolutely clear in their minds that we are fighting for the Premier League.

"I don't think there will be a psychological link between one competition and the other."

One other issue affecting City this week is the scheduling of their FA Cup quarter-final against Wigan for Sunday, March 9, just three days before the game in Barcelona.

It has been reported as a hindrance to City but Pellegrini has another point of view.

He said: "Maybe it's better for us to play on Saturday, but also the international players will only arrive on Thursday after they play for they national team, and that's not good.

"So everything has both sides. We don't have any problem for Sunday."

Pellegrini also confirmed that top scorer Sergio Aguero is due to return to full training next week after four games out with a hamstring injury.